WordNet sense 1 (steady winds blowing from east to west above and below the equator):

trade wind

WordNet sense 2 (people who perform a particular kind of skilled work):

craft

WordNet sense 3 (engage in the trade of):

merchandise

WordNet sense 4 (exchange or give (something) in exchange for):

swap, switch, swop

WordNet sense 5 (do business; offer for sale as for one's livelihood):

deal, sell

WordNet sense 6 (a particular instance of buying or selling):

business deal

WordNet sense 7 (an equal exchange):

barter

WordNet sense 8 (the business given to a commercial establishment by its customers):

patronage